Intervertebral disc (IVD) degeneration is marked by detrimental changes that occur within the IVD structure. IVD degenerative changes appear to initiate within the central region of the IVD known as the nucleus pulposus. Accordingly, many early-stage interventional therapies are being investigated targeting the mitigation or reversal of the degenerative process during its existence in the nucleus pulposus.
Conservative estimates from 2006 indicate that nearly 640,000 individuals were admitted to U.S. hospitals for IVD-associated maladies accounting for $7.6 billion in direct costs. These staggering statistics provide the impetus for research into development of new treatment strategies including surgical techniques and tissue engineering approaches to regenerating the IVD.
Current treatment options include non-surgical management as an initial approach. Unfortunately, non-surgical treatment is only effective in about two-thirds of patients. Failure of such conservative treatment warrants more invasive surgical interventions that can include the removal of a problematic IVD and its replacement with a metallic/polymeric artificial disc. Alternatively, the problematic IVD can be rendered immobile using metal hardware (e.g., rods and screws) thus reducing pain and instability. These surgical procedures are merely palliative and have major consequences associated with their utilization. Moreover, these are typically last resort options for the patient leaving a large gap in treatment options between ineffective non-surgical approaches and current last resort surgical options. To bridge this gap, nucleus pulposus replacement has shown promising advancements as an early-stage treatment to fight IVD degeneration.
Two approaches have been followed thus far in developing nucleus pulposus replacement technology. The first of these is a purely material science approach based upon utilization of synthetic polymers to construct pre-formed or in situ-cured injectable polymeric materials that can replace and mimic the biomechanics of the native nucleus pulposus. The second approach to developing a nucleus pulposus replacement is based upon the principles of tissue engineering and utilizes a combination of cells, scaffolds and various chemical and/or mechanical cues to regenerate a healthy replacement tissue. Limitations to both approaches are becoming increasingly evident; the most prevalent of which is that of device migration and expulsion of synthetic materials due to the fact that they are inanimate and do not integrate intimately with surrounding host tissue.
What is needed in the art is a nucleus pulposus replacement and method of utilizing the nucleus pulposus replacement that addresses such short-comings.